Ground effect vehicle

ABSTRACT

The invention concerns a ground effect vehicle comprising hydrofoils or hydrofoil outer parts ( 18 ) which can pivot about a parallel line relative to the longitudinal axis of the body in order to increase the speed range when flying close the ground. In addition, the hydrofoils and the body can be provided with trailing edge flaps (19) which are articulated so as to pivot about a horizontal axis and, depending on the selected angle of incidence of the hydrofoils or hydrofoil parts, can be controlled as lift-increasing ailerons or flippers.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the US national phase of PCT applicationPCT/DE97/02056 filed Sep. 12, 1997 with a claim to the priority ofGerman application 196 37 544.4 filed Sep. 14, 1996.

FIELD OF THE INVENTION

The invention relates to a ground-effect vehicle with a hull body thathas downwardly directed lateral legs as well as support wings on bothsides.

BACKGROUND OF THE INVENTION

Such ground-effect vehicles are known from German 4,405,152. Asdescribed there, in order to start a ground-effect vehicle an aerostaticlift is first used that is produced in that air is forced through adrive unit into a generally closed space under the supporting lowersurface of the hull so that its super-atmospheric pressure creates lift.Once the ground-effect vehicle is moving forward the air pressure forcesup the flaps of the wings so that the forwardly directed inlet openingallows air into the space between the bottom of the vehicle and thewater or land. Since the sides and rear of this space remain closed, theforward movement of-the vehicle causes a buildup of the aerodynamicallycreated air pressure and the overpressure that creates the aerodynamicground-effect lift. According to the known ground-effect vehicles thereis nonetheless the problem that to produce a dynamic air cushionsufficient to lift the vehicle out of the water a starting velocitydependent on the surface loading is required. Since, relative to air,water is some 800 times more dense, there is about 2 to 2.7 timesgreater resistance opposed to resistance when in the air, and thisincreases as the lift speed increases. In order to achieve this, thesurface loading must be maintained relatively low which leads to largewing sizes (spans). In order to limit the necessary excessive drive loadneeded for starting as compared to that needed for flying, lateral wingsare provided as end plates underneath a relatively large hull body andthese serve also as outrigger floats like on a catamaran float. The rearof the pressure space is closed by the support wing rear edges that areset against the flow direction. A common problem of all ground-effectvehicles is that the increase in lift created by the ground effect withsimultaneous reduction in resistances is only usable when there is arelatively small space between the support surface and the ground orwater. This spacing which can be considered the flying altitude can onlybe maintained when there are no obstructions to fly over. This createsthe risk that the ground-effect vehicle is stalled as a result ofactuating the elevators, which makes recovery like an aircraftimpossible due to the limited flying altitude. In addition when theelevators are lowered there is the danger that the wings of greater spanwhile turning actually touch the water or ground. For this reason onemust not use the maximum wing span that is most useful for starting,which is also a problem as a result of the larger space and theincreased weight, the limited maneuverability when docking, entering aport, and the limited usability in rivers, canals, docks, and the like.In addition the necessary power for starting cannot be used as in anairplane to increase the travel speed. Since the angle is smaller withincreasing air speed, the leading surface relative to the trailingsurface is increasingly smaller at the rear edge so that the increasedlift is lost as well as the automatic altitude stability. This is neededfor the safe use of ground-effect vehicles in order to avoid touchingthe water when flying.

OBJECTS OF THE INVENTION

It is an object of the present invention to improve on the describedground-effect vehicle in that the surface loading at starting isminimized by the greatest possible surface in order to achieve a smallerwater-leaving speed, while increasing same in flight.

SUMMARY OF THE INVENTION

This object is achieved by the ground-effect vehicle with a hull and oneach side a wing of having an outer part that can be pivoted up about arespective rotation axis relative to a respective inner part closer tothe hull so that as a result of the pivoting a surface loadingcorresponding to the current speed is maintained with an optimum settingangle and where each inner wing part has rear flaps that are selectivelycontrollable relative to a hull longitudinal axis, the wing and flapsbeing such that a vertical altitude change can be established withoutchanging the hull position and that rear flaps on the outer wing partsare effective as ailerons, side rudders, and air brakes. The outwardlyarranged parts of the wings are pivotal upward, preferably through anangle up to 90°. In this manner the surface loading can be adjusted tothe current operating conditions by changing the support surfaceproducing the lift. In order to increase the usable speed span,according to the invention the supporting surface can be reduced whilein flight so that the necessary positive setting angle can also bemaintained even at high speed. The rotation axis is selected such thatwhen pivoted up there is minimal resistance near zero. A furtheradvantage is that the wing span can be reduced for entering ports ortraveling in rivers, canals, or locks so that even narrow waterways canbe negotiated. In order to increase the maneuverability of theground-effect vehicle, in particular to avoid collision with obstaclessuch as ships, islands, land masses, bodies floating in the water,icebergs, and the like, it is desirable to have a small turning radiusand rapid altitude changes. To this end the rear-edge flaps on the hulland on the wings, ma be individually controllable symmetrically orasymmetrically to the vehicle longitudinal axis. Separate rear-edgeflaps can be differently deflected in order to assume an inclinedposition for coordinated turning flight. For example the flaps on theinner part that is formed only by the hull or the hull and the innerwing parts, can be operated identically to the landing flaps on aircraftso that the lift and the altitude can be suddenly increased withoutincreasing the angle of incidence. The angular position of the hull andtherefore of the passengers remains the same. Furthermore thiseliminates stalling that is caused by too large an angle of incidence.This is a particular problem with a low flight where there is no room torecover. Furthermore it is not necessary to actuate an elevator to levelout when landing. The necessary altitude control and the level-controlelevator and its controls can be eliminated. As a result of thedecreased cost of control of the ground-effect vehicle special trainingand licenses for the pilot are not needed. The wing and flap arrangementis so selected that altitude changes of the ground-effect vehicle can bemade without changing the angle of the hull which greatly increasespassenger comfort. This is achieved by positive or (preferably) negativesweepback which compensates for the moments about the center of mass ofthe ground-effect vehicle. The flap arrangement can be combined with therear-edge flaps of the outer wing parts so that the altitude and theangle are jointly controlled. By coupling the wing and hull inner flapswith the wing outer flaps one can simultaneously ascend while turning sothat the outer flaps will not hit the water. The rear flaps arranged onthe outer wing parts are in particular so controlled and pivoted thatthey act as ailerons, side rudders, and/or as air brakes. Appropriaterear-edge flaps on the outer wing parts allow a brake effect to beachieved by pivoting them inward so that the flow over the upstreamsupport surface is disturbed and lift is reduced and one descends morequickly to the water. As a result of this braked sudden dropping of theground-effect vehicle the overall stopping distance to water contact isdecreased. The pivot axis of the outer wing parts is set at an anglesuch that when tipped up the effective angle of incidence is so smallthat the thus produced angle produces the least resistance. There isthus a reduction without further production of lift that is neithernecessary nor desirable in these conditions.

Rear edge flaps are arranged on the hull and/or on the wings which arepivotal about horizontal axes. Such rear edges are known basically inaircraft as landing flaps or ailerons. In ground-effect vehicles theyhave the advantage that the rear-edge flaps control the altitude so thatnot only the otherwise necessary elevator can be eliminated, but alsothe pilot need not have to worry about operating it. Actuating therear-edge flaps forces the ground-effect vehicle up so that, as a resultof the greater altitude, contact with the ground or water at the wingtips is impossible.

Further embodiments of the ground-effect vehicle are described in thedependent claims.

According to a further embodiment of the invention the hull is formed asa catamaran having sides in particular formed as floats. Formation as acatamaran produces a very stable watercraft as well as a resistance tocapsizing caused by the wind or likely in a slowly moving ground-effectvehicle.

The outwardly arranged wing parts according to a further embodiment ofthe invention are formed as pivotal two-arm levers and are coupled so onthe inner wing parts that the upwardly pivoted wing part forms adownwardly directed end plate whose free end lies below the inner wingpart and thus outwardly closes a space formed under the inner wing part.This arrangement can produce a surface with a considerable liftpotential for starting the ground-effect vehicle so as to reduce thestarting speed and the necessary horsepower. As the flight speedincreases the angle of incidence decreases to the optimum for the bestflight trajectory. In order not to exceed this angle, which also limitsthe speed with automatic altitude maintenance. the outer wing (wingouter part) is pivoted upward in steps or continuously so that thesurface loading for the actual speed maintains the optimal angle ofincidence. Control of the pivotal wing outer parts (or of the wing) issuch that the angle of incidence until vertical is reduced so that theseproduce as winglets the least possible resistance, but simultaneouslythe end-plate effect described above increases the effective lateralratio. Preferably the pivot axis between the inner wing part and theouter wing part lies in the region of the upper surface of the innerwing part and the common surfaces of the inner wing part and outer wingpart in unpivoted condition extend at an incline to the central(horizontal) plane of the ground-effect vehicle. As a result of thisinclined common surface and the position of the pivot axis, when notpivoted, a common planar wing underside is presented and the inclinedsurfaces of the outer wing part after corresponding upward pivoting formthe inner lateral end plates. As a result the number of parts of thewing and the controls therefor are reduced to a minimum.

The actuator for pivoting the outer wing part is elastically mounted inorder to absorb stresses created by touching the water which are greaterthan the maximum stresses normally encountered during flight. Suchspring elements can be formed by pneumatic devices or elasticintermediate bodies. The amount of spring effect is set such that airloads during flight are withstood without vibration but greaterstresses, e.g. when hitting a wave in the water, are compensated for bydeflection. As a result of this not only the outer surfaces but also theinner surfaces of the wings can be made lighter by reducing theconnecting forces. At the same time the vertical acceleration loads arereduced during startup which leads to a further destressing and increasein passenger comfort.

BRIEF DESCRIPTION OF THE DRAWING

Embodiments of the invention are shown in the drawings.

Therein:

FIG. 1 is a top view of a ground-effect vehicle with a hull formed likea catamaran and two support wings;

FIG. 2 is a front view of the ground-effect vehicle according to FIG. 1in the starting wing position on the left side and various raisedposition of the support wing on the right side;

FIG. 3 is a top view of a ground-effect vehicle with a catamaran-likehull, wings on both sides having pivotal outer wing parts;

FIG. 4 is a front view of the ground-effect vehicle according to FIG. 3with different angular positions of the outer wing parts;

FIG. 5 is a view like FIG. 4 with other settings of the support wings;

FIG. 6 is an arrangement like FIG. 4 or 5 with spring-mounted outer wingparts;

FIG. 7 is a view of the ground-effect vehicle according to FIGS. 4 to 6with both outer wing parts flipped up to reduce span;

FIG. 8 is a top view of a ground-effect vehicle with downwardlydeflected support-wing rear-edge flaps;

FIG. 9 is a section through a support wing with positive flapdeflection;

FIG. 10 is a top view of a ground-effect vehicle with asymmetrical flappositions to set an inclined position;

FIG. 11 is a section through an outer support wing part with differentrear-flap positions;

FIG. 12 is a section like FIG. 11 with a further rearflap position;

FIG. 13 is a rear view of a ground-effect vehicle while turning withsimultaneous altitude change by selective setting of the flaps; and

FIGS. 14 and 15 are top views of a ground-effect vehicle with outer wingparts up and different rear-flap positions of the outer parts.

SPECIFIC DESCRIPTION

The ground-effect vehicles shown in FIGS. 1 to 15 all have a hull havingdownwardly projecting sides formed as floats 16 as well as a center part17 formed as a passenger cabin. On each side of the hull is a wing thatcan be tipped up through up to 90° either wholly or at its outer end.The pivotal parts are shown at 18. Rearward of the hull and of the wingsare rear-edge flaps 19 and 20 that are pivotal about respectivehorizontal axes of the ground-effect vehicle. The ground-effect vehiclecan be set up not as the illustrated catamaran construction but as apure air-cushion vehicle or an air boat. The drive elements as well asthe devices for limiting the air cushion are left out for clarity's sakeand can be made as described in German 4,405,152 to which reference isexpressly made. Dashed line S runs through the center of mass of theground-effect vehicle or that point at which all the various forces areeffective.

When starting and running an air cushion is formed underneath the centerpart 17 and the lowered generally horizontal wings 18 in the spaces 24between the ground-effect vehicle and the water or ground surface 23.The formation of the static or dynamic air cushion is described indetail in German 4,405,152. The wing 18 on the left in FIGS. 1 and 2 aswell as the corresponding right wing in the lower position are in thestarting position in which the biggest possible aerostatic liftcorresponding to the full wingspan is used. As shown for the wing on theright the wings 18 can be pivoted symmetrically or asymmetricallythrough selected angles after the start phase in discrete or continuousstages to achieve cruising speed. A corresponding upward pivoting canalso be used to travel in narrow channels, or to enter a port or lock.In the embodiment of FIG. 2 each of the wings 18 is one piece.

In contrast, FIG. 3 shows an arrangement of wings wherein only the outerwing part 18 is pivotal. The inner wing part 21 is fixed againstpivoting on the hull of the ground-effect vehicle. As shown on the leftin FIG. 4, the entire surface of the wing parts 18 and 21 is notvertical but angled so that, when the outer wing parts 18 are swung up,downwardly directed end plates 26 are formed that laterally delimit theair space 25 in the cruise position. In this manner during the startingphase with an upwardly pivoted wing part one is insured betteraerodynamic lift. FIG. 5 shows an outer wing part swung through adifferent angle with a correspondingly reduced air space 25 in thecruise position.

FIG. 6 shows a hydraulic actuator 27 for setting the pivot angle of theouter wing part 18 that is mounted via a spring element 22 so thatduring gliding over wavy water (see wave 23) the outer wing part 18 canyield when it touches the water. The spring constant is such thataerostatic or aerodynamic forces are not effective but touching a waveis. As described with reference to FIG. 2 when traveling in a harbor,lock, or the like with limited clearance the outer wing parts 18 areswung up.

As seen in FIGS. 9, 11, and 12 the rear-edge flaps 20 of the pivotalwing parts 18 as well as the rear-edge flaps 19 of the inner wing parts21 or of the central hull part 17 are each pivotal about a horizontalaxis. Preferably each of the rear-edge flaps 19 and 20 is independentlypivotal so that symmetrical or asymmetrical flap positions are possible.FIGS. 8 and 9 each show downwardly deflected flaps 19 and 20 that in theillustrated position effect an altitude change for the ground-effectvehicle. FIGS. 10 and 11 show that by asymmetrical flap positioning onthe outer wing parts 18 angled positions of the ground-effect vehicleare settable for turning. To this end rear edge flaps 20 on the sideshown in the right in FIG. 1 are deflected upward and on the oppositeright side downward (see the settings of FIG. 11). The rear-edge flaps19 have in contrast about the same position as the downwardly deflectedrear-edge flaps 20 (FIG. 10 on the right).

The corresponding rear views of the wing and rear-edge flaps shown inFIGS. 10 and 12 can be seen in FIG. 13. With roughly the same deflectionangle of the wing outer parts 18 the rear-edge flap 20 of the left outerwing part 18 is pivoted up while the rear-edge flap 20 on the other sideis pivoted down. The rear-edge flaps 19 on the inner wing parts 21 arepivoted downward differently, that is at different angles, asillustrated by the arrows of different length. The pivoting of therear-edge flaps 19 downward with the illustrated flight turn increasesthe distance from the ground or water surface 23.

FIG. 14 shows how with raised outer wing parts 18 the rear-edge flaps 20act as side rudders. Downward (left) or upward (right) pivoting of therear-edge flaps 20 leads as a result of the vertical position of theouter wing part 18 to a lateral pivoting of the rear-edge flaps 20 toinitiate a flight curve to the left. The positive and negative pivotangles for the rear-edge flaps 20 can be of the exact same size or be ofdifferent sizes.

According to FIG. 15 both rear-edge flaps 20 are pivoted upward relativeto the wing outer parts 18 which as a result of the vertical settingleads to an inward pivoting of the rear-edge flaps 20 which has abraking effect. This braking effect also reduces the lift of the outeredges as a result of the flow, that is the ground-effect vehicle candrop quickly into the water surface.

What is claimed is:
 1. A ground-effect vehicle with a hull and on eachside a wing having a respective outer part can be pivoted up relative toa respective inner part closer to the hull so that as a result of thepivoting a surface loading corresponding to the current speed ismaintained with an optimum setting angle and where each inner wing parthas rear flaps that are selectively controllable relative to a hulllongitudinal axis, the wing and flaps being such that a verticalaltitude change can be established without changing the hull positionand that rear flaps on the outer wing parts are effective as ailerons,side rudders, and air brakes, the outer wing parts being formed aspivotal two-arm levers coupled so on the inner wing parts that, whenupwardly pivoted, the outer wing parts each form a downwardly directedend plate whose free end lies below the respective inner wing part andthus outwardly closes a space formed under the respective inner wingpart.
 2. The ground-effect vehicle according to claim 1 wherein thepivot axis between the inner wing part and the respective outer wingpart lies adjacent an upper surface of the inner wing part and commonsurfaces of the inner wing part and outer wing part in unpivotedcondition extend at an incline to a central plane of the ground-effectvehicle.
 3. The ground-effect vehicle according to claim 2 wherein anactuator for pivoting the outer wing part is elastically mounted inorder to absorb stresses created by touching the water which are greaterthan the maximum stresses normally encountered during flight.
 4. Theground-effect vehicle according to claim 3 wherein the rear-edge flapsof the hull and the inner wing parts are so connected with the rear-edgeflaps of the outer wing parts that, when the ground-effect vehicle istilted by asymmetrical actuation of the outer rear-edge flaps, the innerrear-edge flaps are operated positively to increase spacing above theground or water.